OPOSSUMS University of Georgia Athens, Georgia 30602

Home , Opossum

Jeffrey J. Jackson Extension Wildlife Specialist Warnell School of Forest Resources OPOSSUMS University of Georgia Athens, Georgia 30602

Fig. 1. Opossum, Didelphis virginiana

Damage Prevention and Toxicants Identification Control Methods None are registered. An opossum (Didelphis virginiana) is a Fumigants Exclusion whitish or grayish mammal about the None are registered. size of a house cat (Fig. 1). Underfur is Practical where opossums are entering dense with sparse guard hairs. Its face Trapping structures. is long and pointed, its ears rounded Habitat Modification Leghold traps. and hairless. Maximum length is 40 inches (102 cm); the ratlike tail is Remove cover and plug burrows to Box traps. slightly less than half the total length. reduce frequency of visits by Cage traps. The tail may be unusually short in opossums. northern opossums due to loss by Body-gripping (kill) traps. Frightening frostbite. Opossums may weigh as Shooting much as 14 pounds (6.3 kg); males av- Generally not practical. erage 6 to 7 pounds (2.7 to 3.2 kg) and Effective where firearms are permit- Repellents females average 4 pounds (6.3 kg). The ted. Use a shotgun with No. 6 shot skull is usually 3 to 4 inches (8 to 10 or a .22-caliber rifle. None are registered. cm) long and contains 50 teeth — more than are found in any other North

PREVENTION AND CONTROL OF WILDLIFE DAMAGE — 1994 Cooperative Extension Division Institute of Agriculture and Natural Resources University of Nebraska - Lincoln United States Department of Agriculture Animal and Plant Health Inspection Service Animal Damage Control D-59 Great Plains Agricultural Council Wildlife Committee Walking 2"

Opossum tracks 6" a

Fig. 2. Opossum sign and characteristics: (a) tracks, (b) droppings, and (c) skull.

American mammal. Canine teeth General Biology, (fangs) are prominent. Tracks of both Reproduction, and front and hind feet look as if they were made by little hands with widely Behavior spread fingers (Fig. 2). They may be distinguished from raccoon tracks, in Opossums usually live alone, having a b which hind prints appear to be made home range of 10 to 50 acres (4 to 20 by little feet. The hind foot of an opos- ha). Young appear to roam randomly sum looks like a distorted hand. until they find a suitable home range. Usually they are active only at night. The mating season is January to July in Range warmer parts of the range but may start a month later and end a month Opossums are found in eastern, earlier in northern areas. Opossums central, and west coast states. Since may raise 2, rarely 3, litters per year. 1900 they have expanded their range The opossum is the only marsupial in northward in the eastern United North America. Like other marsupials, States. They are absent from the the blind, helpless young develop in a Rockies, most western plains states, pouch. They are born 13 days after and parts of the northern United mating. The young, only 1/2 inch (1.3 States (Fig. 3). cm) long, find their way into the female’s pouch where they each attach Habitat to one of 13 teats. An average of 7 young are born. They remain in the pouch for 7 to 8 weeks. The young Habitats are diverse, ranging from remain with the mother another 6 to 7 c arid to moist, wooded to open fields. weeks until weaned. Opossums prefer environments near streams or swamps. They take shelter Most young die during their first year. in burrows of other animals, tree Those surviving until spring will breed cavities, brush piles, and other cover. in that first year. The maximum age in They sometimes den in attics and the wild is about 7 years. garages where they may make a Although opossums have a top run- messy nest. ning speed of only 7 miles per hour (11.3 km/hr), they are well equipped Food Habits to escape enemies. They readily enter burrows and climb trees. When threat- Foods preferred by opossums are ani- ened, an opossum may bare its teeth, mal matter, mainly insects or carrion. growl, hiss, bite, screech, and exude a Opossums also eat considerable smelly, greenish fluid from its anal amounts of vegetable matter, espe- glands. If these defenses are not suc- cially fruits and grains. Opossums liv- cessful, an opossum may play dead. ing near people may visit compost When captured or surprised during piles, garbage cans, or food dishes daylight, opossums appear stupid and intended for dogs, cats, and other pets. inhibited. They are surprisingly Fig. 3. Range of the opossum in North America.

D-60 intelligent, however. They rank above dogs in some learning and discrimina- tion tests.

Damage

Although opossums may be consid- ered desirable as game animals, certain individuals may be a nuisance near homes where they may get into garbage, bird feeders, or pet food. They may also destroy poultry, game birds, and their nests.

Fig. 4. Cage trap (set position). Legal Status

Laws protecting opossums vary from state to state. Usually there are open Fig. 5. Leghold trap and sets for opossum. seasons for hunting or trapping opos- Dirt hole set sums. It is advisable to contact local wildlife authorities before removing nuisance animals.

Damage Prevention and Bait Control Methods Leghold trap (coilspring type in set position) Spring levers Exclusion Prevent nuisance animals from entering structures by closing openings to cages and pens that house poultry. Pan adjustment screw Opossums can be prevented from climbing over wire mesh fences by Coil springs installing a tightly stretched electric fence wire near the top of the fence 3 Extra swivel inches (8 cm) out from the mesh. Fas- ten garbage can lids with a rubber strap.

Traps Opossums are not wary of traps and may be easily caught with suitable- Cubby sets sized box or cage traps (Fig. 4). No. 1 or 1 1/2 leghold traps also are effective. Set traps along fences or trail- ways. Dirt hole sets or cubby sets are effective (Fig. 5). A dirt hole is about 3 inches (8 cm) in diameter and 8 inches (20 cm) deep. It extends into the earth at a 45o angle. The trap should be set at the entrance to the hole. A cubby is a small enclosure made of rocks, logs, or a box. The trap is set at the entrance to the cubby. The purpose of the dirt hole or cubby is to position the animal so

D-61 that it will place its foot on the trap. Fig. 6. Body-gripping trap and running pole set. Place bait such as cheese, or slightly spoiled meat, fish, or fruit in the dirt hole or cubby to attract the animal. Using fruit instead of meat will reduce Dog Jaws the chance of catching cats, dogs, or skunks. Spring A medium-sized body-gripping (kill type) trap will catch and kill opossums. Place bait behind the trap in such a way that the animal must pass through the trap to get it. Body- Trigger gripping traps kill the captured animal quickly. To reduce chances of catching pets, set the trap above ground on a running pole (Fig. 6). Body-gripping trap (set position) Shooting

A rifle of almost any caliber or a shotgun loaded with No. 6 shot or larger will effectively kill opossums. Use a light to look for opossums after dark. If an opossum has not been alarmed, it will usually pause in the light long enough to allow an easy shot. Once alarmed, opossums do not run rap- idly. They will usually climb a nearby tree where they can be located with a light. Chase running opossums on foot or with a dog. If you lose track, run to the last place where you saw the animal. Stop and listen for the sound of claws on bark to locate the tree the animal is climbing. Sometimes opossums can be approached quietly and killed by a strong blow with a club, but they can be surprisingly hard to kill in this man- Running pole set ner. They can be taken alive by firmly grasping the end of the tail. If the animal begins to “climb its tail” to reach your hand, lower the animal until it touches the ground. This will distract the opossum and cause it to try to escape by crawling. Opossums can carry rabies, so wear heavy gloves and be wary of bites. Euthanize unwanted animals humanely with carbon dioxide gas, or release them several miles from the point of capture.

D-62 Economics of Damage For Additional Lay, D. W. 1942. Ecology of the opossum in eastern Texas. J. Mammal. 23:147-159. and Control Information McManus, J. J. 1974. Didelphis virginiana. Mammal. Species 40:1-6. No data are available; however, it is Fitch, H. S., and L. L. Sandidge. 1953. Ecology of Reynolds, H. C. 1945. Some aspects of the life usually worthwhile to remove a par- the opossum on a natural area in northeastern Kansas. Univ. Kansas Publ. history and ecology of the opossum in ticular animal that is causing damage. Museum Nat. Hist. 7:305-338. central Missouri. J. Mammal. 26:361-379. Gardner, A. L. 1982. Virginia opossum. Pages Schwartz, C. W., and E. R. Schwartz. 1981. The Acknowledgments 3-36 in J. A. Chapman and G. A. Feldhamer, wild mammals of Missouri, rev. ed. Univ. eds. Wild mammals of North America: Missouri Press, Columbia, 356 pp. biology, management, and economics. The Seidensticker, J., M. A. O’Connell, and A. J. T. Much of the information on habitat, food habits, Johns Hopkins Univ. Press, Baltimore, Johnsingh. 1987. Virginia opossum. Pages and general biology comes from J. J. Maryland. McManus (1974) and A. L. Gardner (1982). 246-263 in M. Novak, J. A. Baker, M. E. The manuscript was read and improved by Hall, E. R., and K. R. Kelson. 1959. The Obbard, and B. Malloch, eds. Wild furbearer Jim Byford and Robert Timm. mammals of North America, Vol. 1. Ronald management and conservation in North Press Co., New York. 546 pp. America. Ontario Ministry Nat. Resour. Figures 1, 2a, 2c, and 3 from Schwartz and Toronto. Schwartz (1981). Hamilton, W. J., Jr. 1958. Life history and economic relations of the opossum (Didelphis Figure 2b by Jill Sack Johnson. marsupialis virginiana) in New York State. Figures 4, 5, and 6 by Michael D. Stickney, from Cornell Univ. Agric. Exp. Sta. Memoirs the New York Department of Environmental 354:1-48. Editors Conservation publication “Trapping Howard, R., L. Berchielli, C. Parsons, and M. Scott E. Hygnstrom Furbearers, Student Manual” (1980), by R. Brown. 1980. Trapping furbearers, student Robert M. Timm Howard, L. Berchielli, C. Parsons, and M. manual. State of New York, Dep. Environ. Gary E. Larson Brown. The figures are copyrighted and are Conserv. 59 pp. used with permission.

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